Ice has always been a problem in the operation of outdoor switches and especially so with switches that remain in one position for a relatively long period of time. In the past, crushing has been relied on to remove ice from contacts or contact shoes. This, of course, requires more energy to develop arm acceleration for effecting the forceful engagement of the blade contact with the contact shoes to crush and shatter the ice.
In U.S. Pat. 3,836,737, a disconnect switch is disclosed having a cam guide on the stationary contact portion of the disconnect switch which cooperates with a cam member on the rotary blade. The cam member cooperating with the follower forces the rotary blade to pivot to forcefully engage the blade contact with the contact shoes. The force exerted by the arrangement is sufficiently strong enough to break ice accumulation.
In U.S. Pat. No. 3,388,225, a disconnect switch is disclosed having a beavertail blade contact of perpendicularly aligned major and minor diameters of specific relationship. The beavertail structure is designed to cooperate with a jaw structure comprised of confronting contact surfaces. The beavertail structure enters between the confronting contact surfaces with the higher of the two beavertail contact surfaces aligned to engage with the jaw contact surface which is substantially straight over its entire length. The substantially straight contact surface is extended to cooperate with the beavertail contact surface to provide a large shearing force which is stated as shearing away ice.
These patents exemplify the various approaches of crushing ice to rid the contact shoes of the highly undesirable element.